Experimental evaluation of the thermal contact conductance of carbon steel at elevated temperatures

Relatively few investigations have been presented on thermal contact conductance (h _c) at elevated temperatures, although such information is important for applications in manufacturing, material processing, and other high-temperature applications. In order to experimentally study the effects of these parameters at elevated temperatures, an experimental apparatus which includes a vacuum system, test apparatus and data acquisition system has been designed and fabricated to measure h _c. Experiments were conducted on carbon steel specimens with a controlled degree of surface characteristics at an average interface temperature of 500-650 K, and an average contact pressure in the range of 0.5-9 MPa. An increase in the contact pressure increased h _c, to a maximum of about 20 kW m ^-2 K ^-1, and a hysteresis in h _c was observed during the pressure cycle. Temperature, however, had little effect on h _c, for the range examined.